Tuesday, May 31, 2016

The latest issue of the Italian science magazine Sapere is all about food. So this seemed a fitting theme for my column on music cognition.

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‘If music be the food of love, play on, give me excess of it”, says Duke Orsino in Shakespeare’s Twelfth Night. The nineteenth-century German music critic Eduard Hanslick wasn’t impressed by that sentiment. It doesn’t matter what music it is, the Duke implies; I just want a load of it, like a big slice of cheesecake, to make me feel good.

But after all, mightn’t music be simply cheesecake for the ears? That is what the cognitive scientist Steven Pinker suggested in his book How the Mind Works. Music, he proposed, is simply a parasite that exploits auditory and cognitive processes which evolved for other reasons, just as cheesecake exploits a primal urge to grab fats and sugars. As he put it, “Music appears to be a pure pleasure technology, a cocktail of recreational drugs that we ingest through the ear to stimulate a mass of pleasure circuits at once.”

After all, Pinker went on, “Compared with language, vision, social reasoning, and physical know-how, music could vanish from our species and the rest of our lifestyle would be virtually unchanged.”

These claims provoked outrage. Imagine comparing Bach’s B minor Mass to an Ecstasy pill! And by suggesting that music could vanish from our species, Pinker didn’t appear much mind if it did. So his remarks were read as a challenge to prove that music has a fundamental evolutionary value, that it has somehow helped us to survive as a species. It seemed as though the very dignity and value of music itself was at stake.

Pinker might be wrong, of course. Indeed, recent research suggests that there might be neurons in our auditory cortex dedicated solely to music, suggesting that sensitivity to music could be a specific evolutionary adaptation, not a byproduct of other adaptive traits. But whether or not that’s so is rather beside the point. Music is an inevitable product of human intelligence, regardless of whether it’s genetically hard-wired. The human mind naturally possesses the mental apparatus needed for musicality, and will make use of these tools whether we intend it or not. Music isn’t something we do by choice – it’s ingrained in our auditory, cognitive, memory and motor functions, and is implicit in the way we construct a sonic landscape from the noises we hear.

So music couldn’t vanish from our species without fundamentally changing our brains. The sixth-century philosopher Boethius seemed to understand this already: music, he said, “is so naturally united with us that we cannot be free from it even if we so desired.” Cheesecake, on the other hand – I can take it or leave it.

Wednesday, May 25, 2016

The 40th anniversary of the publication of Richard Dawkins’ The Selfish Gene is a cause for celebration, as I’ve said.

This anniversary has also reawakened the debate about the book’s title. Do we still think genes are “selfish”? Siddhartha Mukherjee's The Gene makes no mention of the idea, while talking about pretty much everything else. It’s no surprise that Dawkins sticks to his guns, of course. He justifies it in this fashion:

"If you ask what is this adaptation good for, why does the animal do this – have a red crest, or whatever it is - the answer is always, for the good of the genes that made it. That is the central message of The Selfish Gene and that remains true, and reinforced."

This is a statement crafted to brook no dissent. It says nothing about selfishness of genes. It says that adaptations are, well, adaptive, in that they help the organism survive and pass on its genes. But for a gene to be metaphorically selfish, it must surely promote its survival at the expense of other genes.

I’m not going to rehearse again the argument that the “selfish gene” promotes the misconception – which I suspect is now very common – that different genes, not different alleles of the same gene, compete with one another. (In the comment to my blog post above, Matt Ridley points out that there can be exceptions, but at such a stretch as to prove the rule. Still, as Matt says, we're basically on the same page.) The fact is that genes can only propagate with the help of other genes. John Maynard Smith recognized this in the 1970s, and so did Dawkins. He chose the wrong title, and the wrong metaphor, and wrote a superb book about them.

I find it curious that there’s such strong opposition to that fact. For example, I’m struck by how, when the selfish-gene trope is questioned, defenders will often point to rare circumstances in which genes really do seem to be “selfish” – which is to say, where propagation of a gene might be deleterious to the success of an organism (and thus to its other genes). It is hard to overstate how bizarre this argument is. It justifies a metaphor designed to explain the genetic basis of evolutionary adaptation by pointing to a situation in which genetic selection is non-adaptive. You might equally then say that, when genes are truly selfish, natural selection doesn’t “work”.

What is meant to be implied in such arguments is that this selfishness is always there lurking in the character of genes, but that it is usually masked and only bursts free in exceptional circumstances. That, of course, underlines the peril of such an anthropomorphic metaphor in the first place. The notion that genes have any “true” character is absurd. Genetic evolution is a hugely complex process – far more complex than Dawkins could have known in 1976. And complex processes are rarely served well by simple, reductionistic metaphors.

Think of it this way. There are situations in which Darwinian natural selection favours the emergence of sub-optimal fitness (for example, here). This is no big surprise, and certainly doesn’t throw into doubt the fundamental truth of Darwin’s idea. However, we could then, in the spirit of the above, argue that the real character of natural selection is to favour the less-than-fittest, but this is usually masked by the emergence of optimal fitness.

There is an old guard of evolutionary theorists, battle-scarred from bouts with creationism and intelligent design, who are never going to accept this, and who will never see why the selfish gene has become a hindrance to understanding. They can be recognized from the emotive hysteria of their responses to any such suggestion – you will find them clearly identified in David Dobbs’ excellent response to criticisms of his Aeon article on the subject. It is a shame that they have fallen into such a polarized attitude. As the other responses to David’s piece attest, the argument has moved on.

Monday, May 09, 2016

How’s your classical mechanics? Mine’s a bit crap. That’s why I’m having trouble working out the following question.

You have a cylinder that rotates around a horizontal axis, like the sort used to pull up buckets from wells. Around the cylinder is wrapped a rope attached to a weight. As the weight falls and the rope unwinds, you measure the time it takes to descend a certain distance.

Now you increase the mass of the cylinder – say, it’s made from iron, not wood (but of the same size). Does the weight fall more slowly? At risk of embarrassment, I’ll say that I think it does. The torque on the cylinder is the same in both cases, but what changes is the cylinder’s moment of inertia, and thereby (via torque = moment of inertia times angular acceleration) the angular acceleration. So the weight takes longer to descend the same distance when attached to the iron cylinder because the angular acceleration is less.

Also, the greater mass of the cylinder means, via Amonton’s Law, that the friction with the axis is greater in the latter case.

Am I right? Or do I need (it is quite possible) to go back to my A-level mechanics?

The reason I ask is that I am trying to understand a question in the SATs science test (now dropped, by the way) for Year 6, i.e. 11-year-olds.

You might wonder why 11-year-olds are having to grapple with torques and so forth. So am I. But they come up in this question:

Now, I suspect that the answer the pupils are expected to give is that the bigger piece of card incurs more air resistance. That is true. But it is not the only influence at play, since the card obviously adds to the rotor’s mass. So this is a rather complicated question in mechanics.

You might think I’m overthinking the problem. But I can’t see how it is ever a good idea to choose a question for which a little more knowledge makes the problem harder. Or am I just wrong here about the answer?

Elsewhere in the SATs papers you find difficulties that seem to be the result purely of bad questioning. Take this one, from an English Reading and Comprehension test. Pupils have to read the following passage:

Then they are asked

My (10-year-old) daughter was puzzled by this reference to “burning of rocks in space”. What does it mean to burn rocks in space? For one thing, you can’t do it. I mean sure, meteorites will get hot and oxidized as they fall through the atmosphere but not in space. And the frictional heating is not really about burning. “Burning up” is something of a euphemism here, and it does not mean the same thing as “burning”. The intended answer is trivial, of course: “in a flash” just means that the “burning up” happens quickly. But this question is worded in such a way that prevents it from quite making sense.

Is anyone checking this stuff, before it is unleashed on unsuspecting and highly stressed pupils and teachers?